Buyer’s guide to rear lights

Here’s our guide to make sure that you pick a good rear light that will keep you visible this winter

Buyer’s Guide To Rear Lights

If you re looking to ride through the winter, then you re really going to need some good lights to attach to your bike. While you ll be buying a front light1 to light up the road in front of you to let you see where you re going, from a safety point of view, the rear one is perhaps more important, making sure that drivers approaching from behind can always see you and overtake safely.

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So what should you be looking for in a good rear light for your bike in order to make sure that your winter and nightime riding can be as safe as possible?

Legal Requirements

By law, according to the Road Vehicles Lighting Regulations, if you re riding between sunset and sunrise, then you must display a red rear light (as well as white front light, red rear reflector, and two pedals reflectors on each pedal). The rear light must be positioned centrally, 35cm to 150cm from the floor, and visible from the rear. It must also conform with the relevant safety standards, and if flashing emit a minimum of four lumens.

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Of course in reality, these requirements are rarely enforced, and we can t really imagine you being pulled over and reprimanded by the police on account of having your rear light 170cm from the floor. However, it is always wise to conform to the regulations, not only on safety grounds, but just in case you find yourself in court after being involved in a collision.

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One of the most important things to look at in a rear light (or any light for that matter) is how bright it is. While a serious heavy-front light can be expected to pump out thousands of lumens, you really don t need this sort of brightness at the rear. In fact, even the very brightest rear lights are unlikely to pump out much more than 75 lumens, which is more than enough to make you seen.

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Much more important is where all this light is directed. Obviously you want most of it pointing backwards so that cars approaching from behind are able to see you, but sideways visibility should always be a major consideration too. Especially if you re riding in built-up areas then it s really important to make sure that drivers emerging from side junctions can see you as well as those approaching from in front or behind. Therefore look for rear lights which have clear sides in order to avoid taken out from vehicles emerging from side roads.


A key consideration in deciding which rear light to buy is the number of modes that it has, and in general the more modes the better. The most basic of rear lights will often only have a single flashing mode, but pay a little more and you ll often find lights with multiple constant and flashing modes. Rear lights with more than one LED or bulb will often also have modes where one LED is on while the other flashes, as well as different levels of brightness.

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This is useful on a number of levels. Firstly it allows you to be flexible when it comes to light conditions. Slightly counterintuitively, the darker it is the less bright your rear light needs to be, so if you re riding on dark, unlit lanes then you should be easily be spotted even if your rear light is flashing away on its lowest setting. However, if you re riding towards a low sun, and have your rear light on in order to help drivers see you in the brightness of the sun, then you ll want your light to be as bright as possible.

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Multiple modes will also help you to preserve battery life, so if you ve forgotten to charge your rear light and are worried that it might be running low, then you can put it on a lower setting in order to get you home safely. That said, plenty of the better rear lights on the market now come with a low battery mode, which automatically switches the light into a less energy-sapping mode in order to get you home safely.

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Battery life and charging

Even if your rear light does have a low battery mode, battery life still has to be a key consideration. It s really better to be safe than sorry with these sort of things, so the longer the battery life the better, and you should really be looking for a rear light that would be able to cope with at least a week of commutes in order to keep your mind at rest.

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However, probably more important is what batteries the rear light uses, and whether they are rechargeable. If you re looking to get a good, convenient rear light, then it s really worth getting one that is rechargeable. There are plenty around that are powered by coin cell, AA or AAA batteries, but these leave you guessing as to when they might run out of juice.

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The beauty with USB rechargeable ones is that you can just keep the charging cable at home or at work, and plug it in whenever you think your light might need a boost. What s more, plenty of rear lights are now charged using micro-USB cables, which you re likely to already have lying around at home somewhere, meaning that is you lose the cable that comes with the light then it s not the end of the world.


The final big consideration is how your rear light is going to attach to your bike. Basically what you re after is a mount that will keep your rear light firmly in place and pointing in the right direction, so even if you hit some pretty big potholes on some gloomy lanes, your not going to have your nice new light bouncing off into the bushes.

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If you re got a standard round seatpost, then mounting your light shouldn t be too much of an issue (although if you ve got a 31.8mm seatpost then some mounts can be a little tight). However if you re attaching your rear light to a bike with an aero seatpost, then things can be a bit more difficult.

Buyer’s Guide To Rear Lights

If you ve got an aero seatpost, then you might need to improvise on rear light placement

If this is you then look for lights which attach using a long silicon band, or ones which are designed in such a way that they can be mounted either elsewhere on the bike, such as underneath the saddle or on your seatstays.

Our pick of the best rear lights

Buyer’s Guide To Rear Lights

  • September 10, 2015

When it comes to safety, having a good rear light is probably more important than having a good front light, More 10

Buyer’s Guide To Rear Lights

  • November 14, 2014

Embracing the potential offered by rapidly advancing LED and battery technologies, Lezyne has several new lights in its product line-up More 11

Buyer’s Guide To Rear Lights

  • November 8, 2014

Exposure Blaze acts as a bright, compact and easy to use rear light which our tester liked.

Buyer’s Guide To Rear Lights

  • November 3, 2014

Hope do provide extra special pieces of kit that work thoroughly well, though is a rear light with an external More 12

Buyer’s Guide To Rear Lights

  • April 20, 2015

The days are getting longer, but for some lights are still a necessity. The B Twin VIOO Front/Rear Bike Light is a More 13

How much should I spend?

The good news is that while you probably have to go well into three figures in order to buy a top-quality front light that s suitable for the darkest conditions, you don t have to spend nearly this much on your rear light.

In fact thirty quid or so should be more than enough to buy a very good front light that will be bright and include all the key features, while if you re just riding on lit roads then you can get away with much less than this.

How we score

10 Superb, best in its class and we couldn t fault it
9 Excellent, a slight change and it would be perfect
8 Brilliant, we d happily buy it
7 Solid, but there s better out there
6 Pretty good, but not quite hitting the mark
5 Okay, nothing wrong with it, but nothing special
4 A few niggles let this down
3 Disappointing
2 Poor, approach with caution
1 Terrible, do not buy this product


  1. ^ Best front bike lights for under 100 (
  2. ^ >>> Buyer s guide to cycling lights (
  3. ^ >>> Garmin Edge computers: a complete buyer s guide (
  4. ^ >>> Buyer s guide to road bike groupsets (
  5. ^ >>> 15 top tips for commuting to work by bike (
  6. ^ >>> Buyer s guide to road bike tyres (
  7. ^ >>> Brompton: the perfect commuting machine (
  8. ^ >>> Buyer s guide to winter cycling gloves (
  9. ^ >>> The 25 best pieces of cycling advice (
  10. ^ More (
  11. ^ More (
  12. ^ More (
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